The present invention relates to improvements in the operation of burners and gasifiers for mixtures of water and hydrocarbons. An assembly is described which consists of a device to filter and preheat the fuel-oil by passing it through heated water, which device is connected to one or more burners.
The burner which is described operates on the principle that if in a container isolated from the air there is a quantity of any hydrocarbon, preferably a heavy hydrocarbon, and it is heated with an indirect flame to above the boiling point, the hydrocarbon tends to vaporise rapidly. But if at the time there is added a quantity of water, a little less than the volume of the hydrocarbon, and the heat is sufficient so that the water vapour does not cool the mixture, there results from this a combination forming a gas with a high calorific value. It has been shown that the hydrogen of the water combines with the carbon surplus to the combustion, which is of importance in possible industrial applications, all the more so when it is realized that the mixture burns completely without smoke.
If concerned with combustion of a combustible liquid, it must be taken into account that such substances do not burn in this liquid state but that the vapour formed from them burns and the heat liberated thereby ensures that more liquid is evaporated in the combustion zone, and the new vapour maintains the combustion.
Firstly, as may be expected, atoms of hydrogen are formed which react with the molecules of oxygen coming from the air for combustion, forming OH radicals which react in their turn with a molecule of atomic hydrogen, which repeats the process.
In this way, one single atom of hydrogen can form a new atom of the same kind, which sets up a chain reaction process.
To sum up, there is a combustion in which previously there takes place the phenomenon of break up of the fuel-oil and furthermore, with reaction with molecules of water, and in the hollow of the flame a supply of oxygen proceeds from the split water and the OH radicals. The combustion is then rich in hydrogen and oxygen.
A physical aspect of this process of novel combustion is that the particles of water vapour in emulsion with oil, atomise the oil, and in fact an aerosol is formed by the emulsion, which helps combustion.
In fact, the emulsion with the help of the water vapour allows an increase in the partial pressure of the water vapour, with which the energy emitted (linked directly with this partial pressure) increases, in relation to the carbonic anhydride being unatomised by the water. This allows improvement of the transference of heat by radiation (logical increase in the radiation-convection relationship, which is the present concern).
In a thermo-chemical aspect the atoms of carbon of the oil react with the water with a formation of carbon monoxide, diminishing rapidly all possible presence of unburnt particles, the presence of molecules of water already being able to exercise a weakening action on the cracking process of the fuel, so as to avoid the production of soot (last step of the cracking) and thus of unburnt particles.
At the moment of the "slow explosion" (flame) and with the increase of the temperature, there appear short-lived molecular fragments (free radicals, complex and active particles), which rapidly combine in the less heated zones. The presence of emulsified oil in the case considered favours this fact and furthermore it must be taken into account that the atoms of hydrogen favour the increase of velocity of the flame.
This formation of gaseous compounds, methane, ethane, butane, propane, etc., ensures that the combustion is, partly a combustion of gases, very different from the normal aerosol liquid.